Tubular incandescent lamp.



E. R.' KNOWLES. TUBULAR INGANDESCENT LAMP. APPLICATION FILED .1.111.12,1910.

'l 1,028,1 18 Patented June 4, 1912.

2 nvclll'o; MM( zwi @M4 EDWARD R. KNOWLES, 0F NEW YORK, N.

:TUBU'LAR INCANDESCENT LAMP.

spciaation f Letters raient.

Patented-.rune aiuta.

Application ined January 12, 1910. serial No. 537,708.

[o lall whom t may concern:

Be it known that I, EDWARD R. KNOWLES, a citizen of the United States,residing at thecity of New York, in the borough of Brooklyn and State ofNew York, have invented certain new -and' useful Improvements in TubularIncandescent Lamps, of which the following is a full, clear, and exactdescription.

1 0 The present invention pertains' to that kind vof electric lightwherein the body of the.

lamp consists of an exhausted glass tube in closing a filament which isdisposed centrally in a single longitudinal line therein.v

In previous lamps of this ltype there has been great dificulty in sosealing the filament in the tube that it 'will be truly adjusted in theaxis o-f lthe tube, securely held in position and kept uniformlystraight under all thermal conditions. It has also been diiiicult toreduce the physical dimensions of vsuch lamps, andto make 'them in suchman ner that any number 'of lamps can be made sensibly the same and sothat the cost of manufacture will notbe prohibitive.

To obviate these and other defects in lamps of this type as heretoforemade, one object of the invention is to provide a novel means of holdingup the filament within V the tube whereby its accurate adjustment andsafe anchorage are secured previously? to and without interference fromthe sealing of the tube, rendering these operations less difficult ofaccomplishment in the'manufacture of this class of lamps.

A second object of the invention is to' so anchor the lament as to keepit uniformly straight under every thermal or anti-thermal condition,thereby minimizingand preventing its vibration from any cause andfurther precluding its coming into contact with or getting dangerouslynear the walls of the surrounding tube, due to flexure, bowing or mentbeing of eater than ordinary length and corresponding tenuity.

A third object is to reduce to the smallest practicable dimensions themetallic contacts needed to place the lamp electrically in circuit andto so locate the same thatthe lam may be rotated axiallyto any positionan so that one will see vnothing but the glass `tube and filamentlocated therein, in whatever position the lamp is laced and when 'thelamp is lighted there w1l1be seen an unbroken line of light andA a'luminous sheath its mounting.

.attaching means being spaced apart a presagging and thisnotwithstanding the fila thereforshining brightly from end to'. end withno furnishings or appendages to break its continuity or impair itsbrilliancy.

A fourth object is to provide a ready and convenient means ofvattachment for the-` lamp whereby it can be suspended, framed orbracketed and held in any desired position in complete safety as regardsitself and A fifth object is to insure the production of a filament ofuniform length having attaching means thereon adapted for engagementwith anchoring means in the tube, said determined distance, the lamentand attaching' means constituting a unitary structure.

Referring to the drawings which forlm a part of these specifications andin which similar letters or figures are used to designate correspondingparts: Figure 1 is a side elevation'of the lamp showing the manner ofsupporting the filament by spring anchor supports sealed into but notthrough theso wall of the'glass tube and the manner of attaching theleading-in wires tothe spring anchor supports and of sealing them in theends of the tube and attaching the metal Contact' pieces thereto. Figs.2, 3, 4, 5 and- 85 6 show various ways in which the spring anchorsupports can be sealed into but not through the wall of the glass tubeand in which the leading-in wires may be attached thereto. 'Fig 7 is aperspective view showing the flattened spring form ofthe anchor support.Fig. 8 is a longitudinal section of the Alamp showing the filamentsupported by two spring anchor supports, sealed into the glass tube atpoints other than 1n the same 95 straight line. Fig. 9`is a longitudinalsection of the lamp showing the filament sup-- ported by one springanchor support', the other end having its `terminal sealed directlythrough the end of the tube. Fig. 1() 1s a longitudinal section. Fig. 11is a transverse section of the lamp and its fixture contactsillustrating the manner of connecting it to the fixture; said sectionbeing taken on line VA-A of Fig. 10. Fig. 12 is an end view of the bersocket showing the connecting members therein. Fig. 13 is a view of afilament attaching piece before the samel has been rolled up and bent toform a hook thereupon. Fig. 14 is a view of the same' 110 i' to. The

isa view of the same showing the hooked end, and a filament cemented inposition in the tubular portion thereof. Fig. 16, is a perspective `viewof a modified form of a filament attaching piece. t

The body of the lamp and the filament thereof are respectivelydesignated by the reference figures 1 and 2. The former consists of atransparent glass receptacle in the shape of a tube, usually straightand sealedl at both ends. The latter is a filament, p referably ofcarbon, similar to those `in use in the so called bulb type of lamps butrun in a single straight line along the axis of its tubular envelop.however that my anchorages are adapted to support laments vof vothermaterial than carbon.

In Figs. 1 and 8, V-shaped'anchor supports 3, 3 are provided at orneareach end of the tubular lamp body 1 for the purpose of sustainin thefilament 2 in its correct .central position as shown in the variousiigres of the drawings. These V-shaped anchor supports 3, 3, are eachpreferably made L platinumA .section 10 is attached. These spring anchorsupports 3,3, are sealed inte- ,riorly at Dthe tip 5 of the V loop, onenear each end of the tube and at a predetermined distance apart, intothe w'all of the "glass tube,

. but not passing through it,l the tips 5, 5, be 40 ing entirely coveredwith the glass of the tube; or with glass or the like united therepointsof sealing of the tips 5, 5, into the wall of the tube 1 may be at anyypoints on the circumference of the tube l so long as they are therequired distance apart and the h'ooked points 12, 12, are on the axisof the tube 1, thus obviating any necessity for getting them in the samestraight line as .in lamps'heretofore made.

The upper ends 12,112, of these spring anchors 3, 3, are adjusted,during the process of sealing into the wall of the tube, so that theyare exactly in line on the axis of the tube 1.

While the tube 1 isopen at vboth ends and after the spring anchors 3,3,- are adjusted therein, the filament 2 is introduced into the tube 1and securely attached at its end to the inturned ends 12, 12`of thespring anchors' by' a suitable cement joint 12 or in any other approvedmanner. My preferred form of attachin the filament will be hereinafterdescribe A After the filament is secured in position to the springanchors one or both of the spring anchors are bent outwardly toward theopen It may be h'ere noted' ends of the tube thus putting a tension onthe .filament and holding it tense and straight in the axis of the tube.As the of the anchors will relax outwardly or en wardly in theinclosing'tube, it is evident that the lament will always be keptstraight by and between them, the filament f acting when cold orcontracted to keep the anchors under a greater or less tension and.

lwhen hot or expanded having itsslack taken mits the use of wiretherefor of a fair degree,

of stiffness since the springs act in unison. The glass tube lis thensealed on the platinum sections 10, 10 ofthe leading-in wires, anexhausting tube being added at 7 for connection to the vacuum pumps andthe lamp finally sealed up at 7, after exhaustion.

Figs. 2 to 6 inclusive show-various meth- "ods fof sealing the tip 5 ofthe V or Asubstantially V-shaped anchor support into the tube 1. In Fig.2 the anchor support conf sists of a straight portion 3 towhich is at-95 tached at a point above its terminal. 5 the'- leading-in wire 9, 10,the 'terminal 5 being sealed into but not through the .wall of the tube1.

In Fig. 3 the anchor ysupports consist, of a straight portion 3 in whichis va loop 4 through which is hooked the leading-in wire 9, which isi inturn secured' to connection 10.

In Fig. 4 the tip 5 of the V-shaped anchor is. first sealed into a glassbead X which in turn is attached torthe wall of the tube 1.

In Fig. 5 the V-shaped anchor may be made ofpany spring material,'mechanically fastened at its tip to a platinum wire O which in turn issealed at its tip 5 into but not through the wall of the tube 1.

In Fig. l6 a modicat-ion of the V-shapedl anchor 1s shown, .in which-asubstantially flat bottom portion 5.is provided for the anchor. Inwardlybowed arms 4 upwardly extending from 5 are in turn united to therespective arms 3 and 4, the latter corresponding to arms 3 and 4 inthe" several modifications above described. A :recess-5` is preferably"formed with 'under-cut walls whlch `may be pressed into the body of thetube on the inner side thereof,'by a suitable tool. The dat portion-5ofthe anchor is then sprung into this recess and any suitable materlalmay then be used to seal the anchor in place. A Asmall ring or oval 3may 'be provided in connection with this form of device and is adaptedto be sprung up over the shouldered portions of the arms4 to, engage therecesses thereabove when it isu deposed.

sired to place the arm 3 under tension. This form of construction may beof advantage at times, when it is desired to avoid the use of platinum,since a securing -material or cement may be selected which will havesubstantially the same coefficient of expansion as the material of whichthe wire forming the V-shaped anchor in this case is com- By this methodof manufacture it will be seen that all of the work involved in securelyanchoring and adjusting the filament can be accurately erformed beforethe tube needs to be close at either end and yet all of the advantagesof an end seal of the leading-in wires is obtained whereby the lampcanbe placed in any position and without there being any attachment on thelamp to interfere with or obscure the' light. 'By this method ofmanufacture it is also possible to place the spring anchors at the samedistance apart in all lamps, to use the same length filaments in alllamps and to seal all lamps to precisely the same length.

To adapt the lamp for connection in an' electric circuit 'the ends 6, 6are inclosed in metal caps 8, 8 which are cemented or fastened to thebody of the lamp by the cement 11, 11 the leading-in Wires 10, 10 beingsoldered or fastened to the caps 8, 8,.

In Figs. 10 and 11 I have shown a form of connector forming part of areflector or fixture' by means of which the lamp can be quicklyintroduced into or removed from the electric circuit and can be securelyheld in place when so introduced into the electric circuit. The smallsections of ber tube 12 are .slotted partly through at one side, as at13, said slot being s uiiciently wide to admit a cap S'therethrough. Tothe inside of these .tubes are secured spring clips 14 which may beformed simply of strips of wire, united to the said-ber tubes by screws15. Tubular uprights 16 are screwed into each of said tubes, preferablyfor appearance, in the portion thereof adjacent to and in alinement withthe slot therein, and conductive wires `extend upward through the-Vuprights, .and in turn are secured to screws 15. 'I he outer ends ofthefiber tubes may be plugged with small shves of cork 17. The aboveaffords a very simple and inexpensive, but eicient means for makingconnection with and maintaining the lamps iii position. Uprights 16 aresecured by soldering, or in any other suitable manner, to a hollow base.bar 18, which for ornamentalpurposes may be l of brass. Upon the sideof this bar adjacent the lamp sockets is secured a reiiector 19. Thismay be of polished metal or may have secured to the inner sides thereof,strips of porcelain, glass or the like. If the transverseV section ofthe reiector be semi-circul'ar as shown, the lamp sockets shouldpreferably be. placed well below the edges thereof. Ihave thereforeshown a neat unitary structure for supporting the lamp, and one 1n whichobviously the lamp may be inserted merely by snapping it `into positionwithout regard to the particular disposition of any side thereof. Aninsulating thimble y20 is provided midway of the length of the base barand conductive leads are inserted therethrough and respectively extendthrough the hollow base bar and unite or may be integral with the wiresleading downwardly through the uprights at the ends of the reflector.

The preferred form of attaching the filament to the anchor deviceshereinbefore i'efer'red toinvolves the use of small hooked members 21preferably having a tubular filament-engaging portion 22. I prefer toconstruct these in the following manner. A short piece of wire isflattened or rolled down at vone end'23 as shown in Fig. 18. Thefiattened wire is then drawn through a die to roll up the flattenedportion'into tubular form as shown in Fig. 14; and finally the wire endis bent into the form of a hook or loop 24. The filament end is thenintroduced into `tubular portion 22, which is slightly pinched togetherthereupon and cement applied thereto, which makes a. iii-1n connectionand affords excellent electrical contact. The loops 24 are slipped overhooks 12 of the anchors when assembling and cement 1-2 is applied to thejointure in they manner aforesaid. It is obvious that my filament may bejoined to the anchor which may in such case have straight ends by merelycementing the respective ends of said filamentand anchor togetherwithout interosing the tubular connecting piece, and this form ofconstruction has been indicated at 2 in Fig. 6. I may also make theattaching member simply by rolling wire into a'helical coil`as at 25 inFig. 16 -andthen bending an end of said coil into a hook as at 26.

Having described my invention, what I claim is: l

1. In an, incandescent lamp,a filament ancher-forming a currentconductor comprising twov members having free extremities,

the portion of the anchor adjacent the point.

ioe

member, and a: leading-in wire connected with the extremity of the othermember.

2. In an incandescent-electric lamp, a filament anchor consisting `o'f acurrent conductor anchored at a point intermediate its ends onthe bulb.of the lamp to form a pair of free members, a lament connected with onemember, and a leading in wire connected with the other member. 4

3. In an incandescent electric' lamp, a filament anchor consistin of acurrentV conductor bent at a point intermediate its ends i in the 4formof a V and having its bend anchored on the wall of the bulb of the lamp,

y point of union between the members being anchored on the'bulb of thelamp, a lament connected with the free extremity of Vthe spring memberand a leading-in Wire connected With the extremity of the other member.

5. In an incandescent electric lamp, a'lament anchor consisting .of acurrent conductor anchored at a point intermediate its ends on' the bulbof the lamp to form a pair of free members, one member thereof consti-ltuting a spring, a filament connected with the spring member and aleading-in Wire connected with the other member.

6. In an incandescent electric lamp, a ilai ment anchor consistin of 'acurrent conductor bent at a point lntermediate its ends inthe form of aV and having its bend anchored on the Wall of the bulb of the lamp,

one member of the anchor constituting a spring, a filament connected tothe free ex tremity of the spring member of the anchor and extending inone direction and a leading-in Wire connected to the other freeextremity of the anchor and extending oppof sitely to the filament.

7. In an incandescent electric lamp, a filament anchor consistin of acurrent conductor bent at a point intermediate its ends in the form of aV, and having its bend anchored onthe wall of the bulb of the lamp,

one member 'of the anchor constituting a spring, and provided with ahook at the extremity of thespring member, a ilamentv provided with aneye attached to each end of said filament, and attached to the freeextremity of the free member of the'anchor and extending in onedirection, and leading# in-Wires connected to the other free extremityof the anchor extending oppositely to the filament.A y

8. In an incandescent electric lamp, a fila'- ment anchor consisting ofa current conductor'bent at a point intermediate its ends in the form ofa V and having `its bend anchored on the Wall of the'bulb of the lamp,

one member of the anchor constituting a. spring, a filamentprovided withan eye attached to each end Aof said filament, and4 attached to the freeextremity of the free member of the anchor and extending in onedirect-ion, and leading-in-wires connected to4

